Excess thoracic fluid retention can take various forms and can have different causes. As an example, eating salty foods can result in retaining excess fluid in the thorax and elsewhere. Another source of thoracic fluid accumulation is pulmonary edema, which involves a build-up of extravascular fluid in or around a subject's lungs.
One cause of pulmonary edema is congestive heart failure (“CHF”), sometimes referred to simply as “heart failure.” Heart failure is a major health problem—it is estimated that 5 million people suffer heart failure in the United States alone and it is believed to be growing at an approximate rate of 550,000 new cases each year due to, among other things, overall demographic aging. CHF can be conceptualized as an enlarged weakened heart muscle. The impaired heart muscle results in poor cardiac output of blood. Consequently, pulmonary vascular pressures may be elevated to the point that fluid leaks from the pulmonary capillaries into the lungs, affecting normal oxygen exchange. For this reason, pulmonary edema can be an indicator of CHF.
Pulmonary edema can present a medical emergency that requires immediate care. The outlook for pulmonary edema patients can be good if detected early and treated promptly. If left undetected, and consequently untreated, pulmonary edema can lead to extensive hospitalization and even death.